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Wong MH, Rowe-Gurney N, Markham S, Sayanagi KM. Multiple Probe Measurements at Uranus Motivated by Spatial Variability. SPACE SCIENCE REVIEWS 2024; 220:15. [PMID: 38343766 PMCID: PMC10858001 DOI: 10.1007/s11214-024-01050-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/18/2024] [Indexed: 02/22/2024]
Abstract
A major motivation for multiple atmospheric probe measurements at Uranus is the understanding of dynamic processes that create and maintain spatial variation in thermal structure, composition, and horizontal winds. But origin questions-regarding the planet's formation and evolution, and conditions in the protoplanetary disk-are also major science drivers for multiprobe exploration. Spatial variation in thermal structure reveals how the atmosphere transports heat from the interior, and measuring compositional variability in the atmosphere is key to ultimately gaining an understanding of the bulk abundances of several heavy elements. We review the current knowledge of spatial variability in Uranus' atmosphere, and we outline how multiple probe exploration would advance our understanding of this variability. The other giant planets are discussed, both to connect multiprobe exploration of those atmospheres to open questions at Uranus, and to demonstrate how multiprobe exploration of Uranus itself is motivated by lessons learned about the spatial variation at Jupiter, Saturn, and Neptune. We outline the measurements of highest value from miniature secondary probes (which would complement more detailed investigation by a larger flagship probe), and present the path toward overcoming current challenges and uncertainties in areas including mission design, cost, trajectory, instrument maturity, power, and timeline.
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Affiliation(s)
- Michael H. Wong
- Center for Integrative Planetary Science, University of California, Berkeley, CA 94720-3411 USA
- Carl Sagan Center for Science, SETI Institute, Mountain View, CA 94043-5232 USA
| | - Naomi Rowe-Gurney
- NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA
- University of Maryland, College Park, MD 20742 USA
- The Center for Research and Exploration in Space Science & Technology (CRESST II), Greenbelt, MD 20771 USA
- The Royal Astronomical Society, Piccadilly, London, W1J 0BD UK
| | - Stephen Markham
- Observatoire de la Côte d’Azur, 06300 Nice, France
- Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 USA
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2
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Fletcher LN, Cavalié T, Grassi D, Hueso R, Lara LM, Kaspi Y, Galanti E, Greathouse TK, Molyneux PM, Galand M, Vallat C, Witasse O, Lorente R, Hartogh P, Poulet F, Langevin Y, Palumbo P, Gladstone GR, Retherford KD, Dougherty MK, Wahlund JE, Barabash S, Iess L, Bruzzone L, Hussmann H, Gurvits LI, Santolik O, Kolmasova I, Fischer G, Müller-Wodarg I, Piccioni G, Fouchet T, Gérard JC, Sánchez-Lavega A, Irwin PGJ, Grodent D, Altieri F, Mura A, Drossart P, Kammer J, Giles R, Cazaux S, Jones G, Smirnova M, Lellouch E, Medvedev AS, Moreno R, Rezac L, Coustenis A, Costa M. Jupiter Science Enabled by ESA's Jupiter Icy Moons Explorer. SPACE SCIENCE REVIEWS 2023; 219:53. [PMID: 37744214 PMCID: PMC10511624 DOI: 10.1007/s11214-023-00996-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 08/10/2023] [Indexed: 09/26/2023]
Abstract
ESA's Jupiter Icy Moons Explorer (JUICE) will provide a detailed investigation of the Jovian system in the 2030s, combining a suite of state-of-the-art instruments with an orbital tour tailored to maximise observing opportunities. We review the Jupiter science enabled by the JUICE mission, building on the legacy of discoveries from the Galileo, Cassini, and Juno missions, alongside ground- and space-based observatories. We focus on remote sensing of the climate, meteorology, and chemistry of the atmosphere and auroras from the cloud-forming weather layer, through the upper troposphere, into the stratosphere and ionosphere. The Jupiter orbital tour provides a wealth of opportunities for atmospheric and auroral science: global perspectives with its near-equatorial and inclined phases, sampling all phase angles from dayside to nightside, and investigating phenomena evolving on timescales from minutes to months. The remote sensing payload spans far-UV spectroscopy (50-210 nm), visible imaging (340-1080 nm), visible/near-infrared spectroscopy (0.49-5.56 μm), and sub-millimetre sounding (near 530-625 GHz and 1067-1275 GHz). This is coupled to radio, stellar, and solar occultation opportunities to explore the atmosphere at high vertical resolution; and radio and plasma wave measurements of electric discharges in the Jovian atmosphere and auroras. Cross-disciplinary scientific investigations enable JUICE to explore coupling processes in giant planet atmospheres, to show how the atmosphere is connected to (i) the deep circulation and composition of the hydrogen-dominated interior; and (ii) to the currents and charged particle environments of the external magnetosphere. JUICE will provide a comprehensive characterisation of the atmosphere and auroras of this archetypal giant planet.
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Affiliation(s)
- Leigh N. Fletcher
- School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Thibault Cavalié
- Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
| | - Davide Grassi
- Istituto di Astrofisica e Planetologia Spaziali - Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere, 100, I-00133 Roma, Italy
| | - Ricardo Hueso
- Física Aplicada, Escuela de Ingeniería de Bilbao Universidad del País Vasco UPV/EHU, Plaza Ingeniero Torres Quevedo, 1, 48013 Bilbao, Spain
| | - Luisa M. Lara
- Instituto de Astrofísica de Andalucía-CSIC, c/Glorieta de la Astronomía 3, 18008 Granada, Spain
| | - Yohai Kaspi
- Dept. of Earth and Planetray Science, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Eli Galanti
- Dept. of Earth and Planetray Science, Weizmann Institute of Science, Rehovot, Israel 76100
| | | | | | - Marina Galand
- Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2AZ UK
| | - Claire Vallat
- European Space Agency (ESA), ESAC Camino Bajo del Castillo s/n Villafranca del Castillo, 28692 Villanueva de la Cañada (Madrid), Spain
| | - Olivier Witasse
- European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Noordwijk, Netherlands
| | - Rosario Lorente
- European Space Agency (ESA), ESAC Camino Bajo del Castillo s/n Villafranca del Castillo, 28692 Villanueva de la Cañada (Madrid), Spain
| | - Paul Hartogh
- Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany
| | - François Poulet
- Institut d’Astrophysique Spatiale, CNRS/Université Paris-Sud, 91405 Orsay Cedex, France
| | - Yves Langevin
- Institut d’Astrophysique Spatiale, CNRS/Université Paris-Sud, 91405 Orsay Cedex, France
| | - Pasquale Palumbo
- Istituto di Astrofisica e Planetologia Spaziali - Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere, 100, I-00133 Roma, Italy
| | - G. Randall Gladstone
- Southwest Research Institute, San Antonio, TX 78228 United States
- University of Texas at San Antonio, San Antonio, TX United States
| | - Kurt D. Retherford
- Southwest Research Institute, San Antonio, TX 78228 United States
- University of Texas at San Antonio, San Antonio, TX United States
| | | | | | - Stas Barabash
- Swedish Institute of Space Physics (IRF), Kiruna, Sweden
| | - Luciano Iess
- Dipartimento di ingegneria meccanica e aerospaziale, Universit á La Sapienza, Roma, Italy
| | - Lorenzo Bruzzone
- Department of Information Engineering and Computer Science, Remote Sensing Laboratory, University of Trento, Via Sommarive 14, Trento, I-38123 Italy
| | - Hauke Hussmann
- Deutsches Zentrum für Luft- und Raumfahrt (DLR), Berlin, Germany
| | - Leonid I. Gurvits
- Joint Institute for VLBI ERIC, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands
- Aerospace Faculty, Delft University of Technology, Kluyverweg 1, 2629 HS Delft, The Netherlands
| | - Ondřej Santolik
- Department of Space Physics, Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czechia
- Faculty of Mathematics and Physics, Charles University, Prague, Czechia
| | - Ivana Kolmasova
- Department of Space Physics, Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czechia
- Faculty of Mathematics and Physics, Charles University, Prague, Czechia
| | - Georg Fischer
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | | | - Giuseppe Piccioni
- Istituto di Astrofisica e Planetologia Spaziali - Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere, 100, I-00133 Roma, Italy
| | - Thierry Fouchet
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
| | | | - Agustin Sánchez-Lavega
- Física Aplicada, Escuela de Ingeniería de Bilbao Universidad del País Vasco UPV/EHU, Plaza Ingeniero Torres Quevedo, 1, 48013 Bilbao, Spain
| | - Patrick G. J. Irwin
- Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Parks Rd, Oxford, OX1 3PU UK
| | - Denis Grodent
- LPAP, STAR Institute, Université de Liège, Liège, Belgium
| | - Francesca Altieri
- Istituto di Astrofisica e Planetologia Spaziali - Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere, 100, I-00133 Roma, Italy
| | - Alessandro Mura
- Istituto di Astrofisica e Planetologia Spaziali - Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere, 100, I-00133 Roma, Italy
| | - Pierre Drossart
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
- Institut d’Astrophysique de Paris, CNRS, Sorbonne Université, 98bis Boulevard Arago, 75014 Paris, France
| | - Josh Kammer
- Southwest Research Institute, San Antonio, TX 78228 United States
| | - Rohini Giles
- Southwest Research Institute, San Antonio, TX 78228 United States
| | - Stéphanie Cazaux
- Faculty of Aerospace Engineering, Delft University of Technology, Delft, The Netherlands
| | - Geraint Jones
- UCL Mullard Space Science Laboratory, Hombury St. Mary, Dorking, RH5 6NT UK
- The Centre for Planetary Sciences at UCL/Birkbeck, London, WC1E 6BT UK
| | - Maria Smirnova
- Dept. of Earth and Planetray Science, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Emmanuel Lellouch
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
| | | | - Raphael Moreno
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
| | - Ladislav Rezac
- Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany
| | - Athena Coustenis
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
| | - Marc Costa
- Rhea Group, for European Space Agency, ESAC, Madrid, Spain
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3
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Kolmašová I, Santolík O, Imai M, Kurth WS, Hospodarsky GB, Connerney JEP, Bolton SJ, Lán R. Lightning at Jupiter pulsates with a similar rhythm as in-cloud lightning at Earth. Nat Commun 2023; 14:2707. [PMID: 37221170 DOI: 10.1038/s41467-023-38351-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 04/24/2023] [Indexed: 05/25/2023] Open
Abstract
Our knowledge about the fine structure of lightning processes at Jupiter was substantially limited by the time resolution of previous measurements. Recent observations of the Juno mission revealed electromagnetic signals of Jovian rapid whistlers at a cadence of a few lightning discharges per second, comparable to observations of return strokes at Earth. The duration of these discharges was below a few milliseconds and below one millisecond in the case of Jovian dispersed pulses, which were also discovered by Juno. However, it was still uncertain if Jovian lightning processes have the fine structure of steps corresponding to phenomena known from thunderstorms at Earth. Here we show results collected by the Juno Waves instrument during 5 years of measurements at 125-microsecond resolution. We identify radio pulses with typical time separations of one millisecond, which suggest step-like extensions of lightning channels and indicate that Jovian lightning initiation processes are similar to the initiation of intracloud lightning at Earth.
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Affiliation(s)
- Ivana Kolmašová
- Department of Space Physics, Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czechia.
- Faculty of Mathematics and Physics, Charles University, Prague, Czechia.
| | - Ondřej Santolík
- Department of Space Physics, Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czechia
- Faculty of Mathematics and Physics, Charles University, Prague, Czechia
| | - Masafumi Imai
- Department of Electrical Engineering and Information Science, National Institute of Technology (KOSEN), Niihama College, Niihama, Ehime, Japan
| | - William S Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA
| | | | | | - Scott J Bolton
- Space Science Department, Southwest Research Institute, San Antonio, Texas, USA
| | - Radek Lán
- Department of Space Physics, Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czechia
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Orton GS, Tabataba-Vakili F, Eichstädt G, Rogers J, Hansen CJ, Momary TW, Ingersoll AP, Brueshaber S, Wong MH, Simon AA, Fletcher LN, Ravine M, Caplinger M, Smith D, Bolton SJ, Levin SM, Sinclair JA, Thepenier C, Nicholson H, Anthony A. A Survey of Small-Scale Waves and Wave-Like Phenomena in Jupiter's Atmosphere Detected by JunoCam. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2020; 125:e2019JE006369. [PMID: 32728504 PMCID: PMC7380317 DOI: 10.1029/2019je006369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/05/2020] [Accepted: 03/07/2020] [Indexed: 06/11/2023]
Abstract
In the first 20 orbits of the Juno spacecraft around Jupiter, we have identified a variety of wave-like features in images made by its public-outreach camera, JunoCam. Because of Juno's unprecedented and repeated proximity to Jupiter's cloud tops during its close approaches, JunoCam has detected more wave structures than any previous surveys. Most of the waves appear in long wave packets, oriented east-west and populated by narrow wave crests. Spacing between crests were measured as small as ~30 km, shorter than any previously measured. Some waves are associated with atmospheric features, but others are not ostensibly associated with any visible cloud phenomena and thus may be generated by dynamical forcing below the visible cloud tops. Some waves also appear to be converging, and others appear to be overlapping, possibly at different atmospheric levels. Another type of wave has a series of fronts that appear to be radiating outward from the center of a cyclone. Most of these waves appear within 5° of latitude from the equator, but we have detected waves covering planetocentric latitudes between 20°S and 45°N. The great majority of the waves appear in regions associated with prograde motions of the mean zonal flow. Juno was unable to measure the velocity of wave features to diagnose the wave types due to its close and rapid flybys. However, both by our own upper limits on wave motions and by analogy with previous measurements, we expect that the waves JunoCam detected near the equator are inertia-gravity waves.
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Affiliation(s)
- Glenn S Orton
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | | | | | | | | | - Thomas W Momary
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | - Andrew P Ingersoll
- Division of Geological and Planetary Sciences, California Institute of Technology Pasadena CA USA
| | - Shawn Brueshaber
- College of Engineering and Applied Sciences, Western Michigan University Kalamazoo MI USA
| | - Michael H Wong
- Department of Astronomy, University of California Berkeley CA USA
- SETI Institute Mountain View CA USA
| | - Amy A Simon
- NASA Goddard Space Flight Center Greenbelt MD USA
| | - Leigh N Fletcher
- Department of Physics and Astronomy, University of Leicester Leicester UK
| | | | | | - Dakota Smith
- National Center for Atmospheric Research Boulder CO USA
| | - Scott J Bolton
- Space Science and Engineering Division, Southwest Research Institute San Antonio TX USA
| | - Steven M Levin
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | - James A Sinclair
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | - Chloe Thepenier
- Glendale Community College Glendale CA USA
- Now at the University of California Davis CA USA
| | | | - Abigail Anthony
- Golden West College Huntington Beach CA USA
- Now at the University of California Berkeley CA USA
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6
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Fletcher LN, Kaspi Y, Guillot T, Showman AP. How Well Do We Understand the Belt/Zone Circulation of Giant Planet Atmospheres? SPACE SCIENCE REVIEWS 2020; 216:30. [PMID: 32214508 PMCID: PMC7067733 DOI: 10.1007/s11214-019-0631-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/24/2019] [Indexed: 05/20/2023]
Abstract
The atmospheres of the four giant planets of our Solar System share a common and well-observed characteristic: they each display patterns of planetary banding, with regions of different temperatures, composition, aerosol properties and dynamics separated by strong meridional and vertical gradients in the zonal (i.e., east-west) winds. Remote sensing observations, from both visiting spacecraft and Earth-based astronomical facilities, have revealed the significant variation in environmental conditions from one band to the next. On Jupiter, the reflective white bands of low temperatures, elevated aerosol opacities, and enhancements of quasi-conserved chemical tracers are referred to as 'zones.' Conversely, the darker bands of warmer temperatures, depleted aerosols, and reductions of chemical tracers are known as 'belts.' On Saturn, we define cyclonic belts and anticyclonic zones via their temperature and wind characteristics, although their relation to Saturn's albedo is not as clear as on Jupiter. On distant Uranus and Neptune, the exact relationships between the banded albedo contrasts and the environmental properties is a topic of active study. This review is an attempt to reconcile the observed properties of belts and zones with (i) the meridional overturning inferred from the convergence of eddy angular momentum into the eastward zonal jets at the cloud level on Jupiter and Saturn and the prevalence of moist convective activity in belts; and (ii) the opposing meridional motions inferred from the upper tropospheric temperature structure, which implies decay and dissipation of the zonal jets with altitude above the clouds. These two scenarios suggest meridional circulations in opposing directions, the former suggesting upwelling in belts, the latter suggesting upwelling in zones. Numerical simulations successfully reproduce the former, whereas there is a wealth of observational evidence in support of the latter. This presents an unresolved paradox for our current understanding of the banded structure of giant planet atmospheres, that could be addressed via a multi-tiered vertical structure of "stacked circulation cells," with a natural transition from zonal jet pumping to dissipation as we move from the convectively-unstable mid-troposphere into the stably-stratified upper troposphere.
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Affiliation(s)
- Leigh N. Fletcher
- School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Yohai Kaspi
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, 76100 Israel
| | - Tristan Guillot
- Université Côte d’Azur, OCA, Lagrange CNRS, 06304 Nice, France
| | - Adam P. Showman
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 USA
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Imai M, Kolmašová I, Kurth WS, Santolík O, Hospodarsky GB, Gurnett DA, Brown ST, Bolton SJ, Connerney JEP, Levin SM. Evidence for low density holes in Jupiter's ionosphere. Nat Commun 2019; 10:2751. [PMID: 31227707 PMCID: PMC6588597 DOI: 10.1038/s41467-019-10708-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 05/28/2019] [Indexed: 11/12/2022] Open
Abstract
Intense electromagnetic impulses induced by Jupiter’s lightning have been recognised to produce both low-frequency dispersed whistler emissions and non-dispersed radio pulses. Here we report the discovery of electromagnetic pulses associated with Jovian lightning. Detected by the Juno Waves instrument during its polar perijove passes, the dispersed millisecond pulses called Jupiter dispersed pulses (JDPs) provide evidence of low density holes in Jupiter’s ionosphere. 445 of these JDP emissions have been observed in snapshots of electric field waveforms. Assuming that the maximum delay occurs in the vicinity of the free space ordinary mode cutoff frequency, we estimate the characteristic plasma densities (5.1 to 250 cm−3) and lengths (0.6 km to 1.3 × 105 km) of plasma irregularities along the line of propagation from lightning to Juno. These irregularities show a direct link to low plasma density holes with ≤250 cm−3 in the nightside ionosphere. Intense electromagnetic impulses induced by Jupiter’s lightning can produce both low-frequency dispersed whistler emissions and non-dispersed radio pulses. Here, the authors show Jupiter dispersed pulses associated with Jovian lightning that are evidence of low density holes in Jupiter’s ionosphere.
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Affiliation(s)
- Masafumi Imai
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, 52242, USA.
| | - Ivana Kolmašová
- Department of Space Physics, Institute of Atmospheric Physics, The Czech Academy of Sciences, 117 20, Prague, Czechia.,Faculty of Mathematics and Physics, Charles University, 110 00, Prague, Czechia
| | - William S Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, 52242, USA
| | - Ondřej Santolík
- Department of Space Physics, Institute of Atmospheric Physics, The Czech Academy of Sciences, 117 20, Prague, Czechia.,Faculty of Mathematics and Physics, Charles University, 110 00, Prague, Czechia
| | - George B Hospodarsky
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, 52242, USA
| | - Donald A Gurnett
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, 52242, USA
| | - Shannon T Brown
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Scott J Bolton
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, 78238, USA
| | - John E P Connerney
- Space Research Corporation, Annapolis, MD, 21403, USA.,NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - Steven M Levin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91125, USA
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